XTYP_ADVREQ transaction
The XTYP_ADVREQ transaction informs the server that an advise transaction is outstanding on the specified topic name and item name pair and that data corresponding to the topic name and item name pair has changed. The system sends this transaction to the Dynamic Data Exchange (DDE) callback function, DdeCallback, after the server calls the DdePostAdvise function.
#define XCLASS_DATA 0x2000
#define XTYPF_NOBLOCK 0x0002
#define XTYP_ADVREQ (0x0020 | XCLASS_DATA | XTYPF_NOBLOCK )
Parameters
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uType
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The transaction type.
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uFmt
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The format in which the data should be submitted to the client.
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hconv
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A handle to the conversation.
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hsz1
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A handle to the topic name.
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hsz2
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A handle to the item name that has changed.
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hdata
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Not used.
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dwData1
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The count, in the low-order word, of XTYP_ADVREQ transactions that remain to be processed on the same topic, item, and format name set within the context of the current call to the DdePostAdvise function. The count is zero if the current XTYP_ADVREQ transaction is the last one. A server can use this count to determine whether to create an HDATA_APPOWNED data handle to the advise data.
The low-order word is set to CADV_LATEACK if the DDEML issued the XTYP_ADVREQ transaction because of a late-arriving DDE_ACK message from a client being outrun by the server.
The high-order word is not used.
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dwData2
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Not used.
Return value
The server should first call the DdeCreateDataHandle function to create a data handle that identifies the changed data and then return the handle. The server should return NULL if it is unable to complete the transaction.
Remarks
A server cannot block this transaction type; the CBR_BLOCK return code is ignored.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|
See also
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Reference
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Conceptual